CCL2 and obesity due to melanocortin 4 receptor deficiency: Adipose tissue inflammation in obesity is characterized by an increase in pro-inflammatory cytokines, such as tumor necrosis factor-α (TNFα), interleukin-6 (IL-6), and monocyte chemotactic protein-1 (MCP-1), along with macrophage or T immune cell accumulation, which contribute to the development and exacerbation of type 2 diabetes mellitus (T2DM), hypertension, atherosclerosis, and other metabolic disorders [6,7].